Background: Recently there has been a renewed interest in defining the boundaries and subdomains of the negative syndrome in schizophrenia and new scales have been asked for. Apathy is one of the symptoms in focus. The Apathy Evaluation Scale (AES) with its clinical version (AES-C) is one of the most used scales in an interdisciplinary context, but it has never previously been used in a population with first episode psychosis. The main aims of this study were to examine the psychometric properties of the AES-C and its relationship to the Positive and Negative Syndrome Scale (PANSS).
Methods: A total of 104 patients with first episode psychosis from the ongoing Thematic Organized Psychosis Research (TOP) study were included.
Results: A factor analysis of the AES-C identified three subscales: Apathy, Insight and Social Contacts. Only the Apathy subscale showed satisfactory psychometric properties and showed acceptable convergent and discriminate properties by correlating strongly with the apathy-related items of the PANSS.
Conclusions: This study shows that the AES-C measures more than one dimension. The main factor, the Apathy subscale, can however be used to assess apathy in first episode psychosis patients in the ongoing work of refining the subdomains of the negative syndrome.